Mitsubishi 3000GT Service Manual page 854

SERVICE BRAKES - Anti-lock Braking System Troubleshooting
No. Trouble condition
4
After the ignition key is turned to the "ON"
position, it blinks once and then illumi-
nates when it is turned to the "START'
position. When the key is returned to the
"ON" position, the light blinks again.
(Blinking with the ignition key in the "ON"
position is synchronized with operation
noise of the valve relay.)
ABS
warning
light
Ignition
ACC, LO?-
Does the ABS warni
when starting to drive
Is there one-sided braking, insufficient -
braking force or malfunction of ABS op-
eration?
Yes
Trouble condition
One-sided braking
lnsuff icient braking force
Decline in ABS function
ABS sometimes functions even when
there is no sudden braking. (ABS opera-
tion vibration is transmitted.)
Major causes
Break in harness for ECU warning
l
light drive circuit
Malfunction of ECU
l
Yes
valve [due to self test at start-up or mal-
function of wheel speed sensor]
No
CONTINUED ON NEXT PAGE
Major causes
Hydraulic line in HU is clogged.
l
Mechanical lock of HU solenoid valve
Hydraulic line in HU is clogged.
l
Malfunction in HU solenoid valve op-
l
eration
Insufficient wheel speed sensor out-
l
put voltage (sensor malfunction, too
large a gap between sensor rotor,
missing rotor teeth)
Malfunction of ABS ECU
l
TSB
Revision
Remedy
Check, using flow
chart D (Refer to
Remedy
Check HU operation and, if
necessary, replace HU. If HU
is normal, check structural
parts for normal braking.
Check wheel speed sensor
(Refer to P.35-60.) and, if nec-
essary, replace sensor, adjust
gap or replace rotor.
If tests indicate that there are
no mechanical or electrical
failures, replace the ECU.